[CentOS] [semi-OT] C7 Possible bug but I can't determine what tool has the problem

Wed Jan 15 17:38:37 UTC 2020
Alessandro Baggi <alessandro.baggi at gmail.com>

Il 15/01/20 17:51, Jon Pruente ha scritto:
> On Wed, Jan 15, 2020 at 10:18 AM Alessandro Baggi <
> alessandro.baggi at gmail.com> wrote:
>
>> I made several test to see what happens and noticed that removing -S
>> (--sparse) from rsync command problem does not occour.
>> In another test, thinking about a problem on 0ed file, I tried file
>> generation using /dev/urandom then /dev/zero and running rsync -avS the
>> problem is disappeared.
>>
> https://wiki.archlinux.org/index.php/Sparse_file#Creating_sparse_files
>
> In short, rsync is being told to create sparse files with the -S flag, so
> it does.  Could you share what you did with the urandom then zero test you
> mentioned? I'm curious what exact sequence of commands you used.
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Hi Jon,
I wrote in the first mail the script with the current order of command 
that I used. Try to run in a bash script and you will see the result.

If not my sequence is:

dd if=/dev/zero of=src/testfile bs=1M count=100
rsync -avS src/ dest/
du -h dest/testfile
du -b dest/testfile

for urandom:

dd if=/dev/urandom of=src/testfile bs=1M count=100
rsync -avS src/ dest/
du -h dest/testfile
du -b dest/testfile

without --sparse the same as first sequence without -S option.

But why du reports 0M when with -b reports correct bytes and why this 
happens only with zeroed file?




I don't know if in the original post mail script